Process for preparing triarylmethane dyes



' tion Serial No. 155,098 describes the prepa-.

' ent No. 289,571).

Patented Aug. 12, 1930 UNITED STATES PATENT OFFICE FRANK WILLIAM LINGHAND ERNEST HARRY RODD, OF BLAGKLEY JMANCHESTEB,

ENGLAND, ASSIGNORS TO BRITISH DYES'LUFFS CORPORATION LIMITED, OF MANCHESTER, ENGLAND rRooEss FOR PREPARING TRIARYLMETI-IANE DYES No Drawing.Application'filed. October 1928, Serial No. 315,100, and inGreat BritainNovember The specification accompanying applicaration of carbinols ofthe triarylmethane series by condensing sodium derivatives oftetra-alkyldiaminobenzophenones with aromatic chloro compounds. In ourpreferred process, as described in the examples, we used toluene assolvent, working at a temperature of 85100 C. It was subsequentlydiscovered that under these conditions by-products are formed,especially diarylbenzyl-carbinols, produced through the interaction ofthe sodium derivative of the ketone with toluene (see thespecificationof British Letters Pat- By further experiments We have discovered thatthe condensation of the chloro compound with the ketylcompound proceedsequally as well at a lower temperature, e. g. 60 0., as at the highertemperature previously used, although at the lower tem-; perature' thesodiumis in the solid form, not

fluid as at the higher temperature. Working at 60 C. we prefer to usebenzene as solvent since it is cheaper and at the same time gives v riseto a lesser quantity of by-products. Un-

der our new conditions we therefore obtain a higher yield and a purerproduct. The following example illustrates the improved method ofworking. The partsare by weight- EwampZe.A mixture of 26.8 parts ofMichlers ketone, 17.0 parts of l-ohloro-mxylene, 100 parts of benzeneand 4.6 parts of sodium, in the form of granules, wire or small pieces,is heated in a closed Vessel with vigorous stirring at 60 C. for 10-12hours. If T any small particles of sodium remain they The same method ofprocedure can be ap- I plied to the condensation of ohlorobenzene,chlorotoluene, chloroxylenes, chloroanisoles,

chloronaphthalenes and the like with the sodium derivatives oftetramethylor tetraethyldiaminobenzophenones.

What we claim and desire to secure by Let-,

ters Patent is A process for the manufacture of triarylcarbinols, whichin the form of their salts are basic dyestuffs, consisting in reacting atetraalkyldiaminodiaryl ketone with an alkali metal and with an arylhalide in presence of benzene as solvent and at a temperature notexceeding about 60 C.

In testimony whereof we aflix our signatures.

FRANK WVILLIAM LINCH. ERNEST HARRY RODD.

